Huh, you could heat air, I'm not sure how that would help you, since it's compressive heating that does most of the damage at those speeds, with a well designed craft. But yeah, long wave IR around 7 Micrometer wavelenth soaks into the water vapor, which would theoretically expand it, causing convection... Still not sure how that helps?

_________________"You can't have everything, where would you put it?" -Steven Wright.

But that torpedo works by pushing water out of the way using air (or other gases). If you push air out of the way using another gas, you're not going to improve your drag by much if anything. You'd need a way to replace the air with a vacuum in front of the ship, without pushing it aside directly.

_________________Say, can you feel the thunder in the air? Just like the moment ’fore it hits – then it’s everywhereWhat is this spell we’re under, do you care? The might to rise above it is now within your sphereMachinae Supremacy – Sid Icarus

So, you ionise the air in front of you. It'd still be in the way, just now consisting of charged particles. What am I missing?

_________________Say, can you feel the thunder in the air? Just like the moment ’fore it hits – then it’s everywhereWhat is this spell we’re under, do you care? The might to rise above it is now within your sphereMachinae Supremacy – Sid Icarus

By violently expanding air it is not in your way. If I could beam a laser that does not get absorbed by air into the ship from the ground. This could be converted into a different frequency and then emitted in a frequency that is absorbed by air.

The idea is to launch a very heavy ship with only ground based power and scramjets.

If a system like this could be made on a very small scale...... It could work on a very large scale.... If all launch energy is made on earth then the ship could be very light. A spaceport of a massive scale built by all nations would free us from earth and help ensure that humanity has back up colonies so extinction is very unlikely.

Heavy metal ships can shield radiation much better then light ones.

If I pulsed and electromagnet can't I pull or push ions?

_________________Let not the bindings of society hold you back from improving it.... the masses follow where the bold explore.

I'd expand the air behind the ship, and skip the railgun, unless this was some sort of weapon. Cannons are really less useful for launching something you care about being destroyed in the process, and better for their classical use, destroying things.

_________________"You can't have everything, where would you put it?" -Steven Wright.

I'd expand the air behind the ship, and skip the railgun, unless this was some sort of weapon. Cannons are really less useful for launching something you care about being destroyed in the process, and better for their classical use, destroying things.

Mach 10 won't do it, think Mach 25 @ sea level, and with the drag associated with doing this in an atmosphere, probably a lot higher.

I agree, for the most part. Especially the Fuel, if it doesn't compression detonate from the gees. (Most substances that energy dense are sensitive to shock.) People aren't so hardy, though, so such a launch facility is best for cargo, or a weapon. You'd need something else to get crews up there.

A tuned beam could move the air out of the way, but I'm not sure how much this would help the muzzle barrier. Also, you're talking about a lot of energy, probably more than the railgun uses. At minimum depth, you're talking about a column of air as wide as the ship, and about 100 miles long. If your ship leaves at a constant LEO velocity, that'll take about 5 minutes to clear, while maintaining this tunnel against the entire atmosphere pushing back in the whole time.

So, you're using a railgun to save energy (in the form of fuel, which also has mass,) then multiplying the launch energy by at least an order of magnitude to minimize a side effect of using a railgun in an atmosphere. Then, you're talking about powering this ship with a Scramjet. In a column of pre-heated low density air created by the railgun, a ramjet would overheat, and suffocate, so that part of the combination at least is impossible. The trick of making the passage through the air makes the scramjet not work.

_________________"You can't have everything, where would you put it?" -Steven Wright.